Turbine inlet screen



Nov. 14, 1967 I B. A. DUERR 3,352,104

TURBINE INLET SCREEN Filed June 27, 1966 2 Sheets-Sheet l I N VENTOR.

A TTORNE Y B. A. DUERR By 57100 X. bad? ATTORNEY Nov. 14, 1967 Filed June 27, 1966 United States Patent O of Delaware Filed June 27, 1966, Ser. No. 560,621 7 Claims. (CI. 6013) This invention relates to a turbine inlet screen and more particularly to a screen for protecting the blades of an exhaust gas driven turbocharger from potentially damaging particulate matter in the exhaust gases.

When an exhaust gas driven turbocharger is provided on an internal combustion engine it is often desirable to provide a screen assembly at the inlet to the turbine. In the event of a failure in the engine, such as breakage of an exhaust valve, the screen will prevent pieces of the valve from being driven through the turbine and damaging the turbine blades.

When such a screen is placed across the turbine inlet, it is of course subjected to the high temperatures of the exhaust gases. The screen must be so constructed and mounted that expansion of the screen may take place without creating thermal stresses of suflicient magnitude to break the screen. In one prior art form of screen, a solid plate having openings drilled t-herethrough is mounted on a plurality of flexible metal strips which allow such thermal expansion.

In this invention, a screen is provided which has substantially greater flow area through the screen while still permitting thermal expansion. In the disclosed embodiments, this is accomplished by providing a plurality of approximately concentric arcuate strips, the inner strips being supported by the outer strips to permit relative expansion.

The details as well as other objects and advantages of this invention appear in the following description and in the drawings in which:

FIGURE 1 is a view of an engine having an exhaust gas driven turbocharger;

FIGURE 2 is a view of one embodiment of the screen provided by this invention in which a spirally wound strip provides a plurality of arcuate screen portions between a hub and a mounting flange;

FIGURE 3 is a view along lines 3-3 of FIGURE 2 showing the means by which the strip is secured to the hub and the mounting flange;

FIGURE 4 is a view similar to FIGURE 2 of an alternative embodiment in which the arcuate strip portions are formed by an electrochemical machining process; and

FIGURE 5 is a view along line 5--5 of FIGURE 4 illustrating the support of the arcuate strip portions.

Referring first to FIGURE 1, an engine It) is provided with a turbocharger having an air compressor 12 driven by a turbine 14. Turbine 14 is driven by exhaust gases from the engine flowing through an exhaust manitold 16. A screen 18 is disposed in the exhaust gas flow path at the inlet to turbine 14.

Referring now to the embodiment of FIGURES 2 and 3, a screen 18 has a rim 20 defining an exhaust gas flow path therethrough. Disposed within rim 20 is a hub 22 having a plurality of apertures 24 formed therethrough. A strip 26 is spirally wound between hub 22 and rim 20.

A series of dowels 28 are secured to and extend outwardly from hub 22 and a second series of dowels 30 are secured to and extend inwardly from rim 20. Dowels 28 and 30 extend through openings 32 in the strip 26, supporting the strip 26 but allowing radial movement along the dowels. A plurality of washer-like spacers 34 3,352,104 Patented Nov. '14, 1967 are provided on each dowel to maintain an open, evenly dispersed network between the hub 22 and the rim 20.

Referring to FIGURE 2, the strip 26 may be considered as a plurality of radially spaced arcuate portions, the outermost group A of which is supported solely by the dowels 30 and the innermost group B of which is supported solely by the dowels 28. An intermediate group C of the arcuate portions is supported by both dowels 28 and 30. Thus the innermost group B and the hub 22 are supported by the intermediate group C and the dowels 30. The hub 22 and the innermost group of arcuate strip portions may thus expand relative to the rim 20 without undergoing thermal stresses suflicient to break the screen assembly.

Referring now to the embodiment of FIGURES 4 and 5, a plate 36 is formed into a rim portion 38, a hub portion 40, a plurality of arcuate strip portions 42, a series of inner spoke portions 44, and a series of outer spoke portions 46. This may be accomplished by wellknown electrochemical machining processes. As described above in connection with the embodiments of FIGURES 2 and 3, an outer arcuate strip A is supported solely by the outer spokes 46, an inner group B is supported solely by the inner spokes 44, and an intermediate group C is supported both by spokes 44 and 46. Thus the inner group B may expand without suflering thermal stresses sufficient to damage the screen.

The turbine inlet screen provided by this invention elfectively protects the turbine from potentially damaging particulate material in the exhaust gases and does not materially increase the back pressure of the exhaust gases. The screen is so constructed that the center portions of the screen, which are maintained at higher temperature than the outer portions, may expand without failing due to high thermal stresses.

I claim:

1. For an internal combustion engine having an exhaust gas driven turbine, a screen adapted to cover the inlet to said turbine and protect said turbine from potentiallydamaging particulate matter in the exhaust gases, said screen comprising a rigid rim portion adapted for mounting at the inlet to said turbine, a hub portion disposed within said rim, a plurality of substantially arcuate strip portions radially spaced between said rim and said hub, the spacing between said strip portions providing openings for exhaust gas flow through said screen, said strip portions including a radially inner strip portion, a radially outer strip portion, and an intermediate strip portion disposed between said inner and outer strip portions, and means supporting said strip portions including first spoke means extending radially inwardly from said rim and supporting said outer strip portion and second spoke means extending radially outwardly from said hub and supporting said inner strip portion, said intermediate strip portion being supported by both said first and second spoke means to permit expansion of said screen upon an increase in temperature.

2. The screen of claim 1 comprising a single plate of material from which arcuate portions have been removed to form said rim, hub, and strip portions and the supporting means.

3. The screen of claim 1 wherein said arcuate strip portions are concentric.

4. The screen of claim 1 which includes a strip spirally wound about said hub portion Within said rim portion and forming said substantially arcuate strip por- Y tions.

5. The screen of claim 4 wherein said spoke means include dowels extending radially through said strip to permit portions of said strip to move in a radial direction upon a change in temperature.

6. The screen of claim 5 which further includes spacing members supported on said dowels between portions of said strip to maintain a predetermined spacing between the portions of said strip.

7. The screen of claim 1 wherein said hub portion has axially extending openings permitting flow of exhaust gases therethrough.

References Cited UNITED STATES PATENTS 2, 680,345 6/1954 Frost 6039.09 2,695,074 11/1954 Kelley 60-39.09 X 2,709,499 5/1955 Bell et al 6039.09 X

CARLTON R. CROYLE, Primary Examiner 

1. FOR AN INTERNAL COMBUSTION ENGINE HAVING AN EXHAUST GAS DRIVEN TURBINE, A SCREEN ADAPTED TO COVER THE INLET TO SAID TURBINE AND PROTECT SAID TURBINE FROM POTENTIALL DAMAGING PARTICULATE MATTER IN THE EXHAUST GASES, SAID SCREEN COMPRISING A RIGID RIM PORTION ADAPTED FOR MOUNTING AT THE OUTLET TO SAID TURBINE, A HUB PORTION DISPOSED WITHIN SAID RIM, A PLURALITY OF SUBSTANTIALLY ARCUATE STRIP PORTIONS RADIALLY SPACED BETWEEN SAID RIM AND SAID HUB, THE SPACING BETWEEN SAID STRIP PORTIONS PROVIDING OPENINGS FOR EXHAUST GAS FLOW THROUGH SAID SCREEN, SAID STRIP PORTIONS FOR EXHAUST GAS FLOW THROUGH SAID SCREEN, SAID RADIALLY OUTER STRIP PORTION, AND AN INTERMEDIATE STRIP PORTION DISPOSED BETWEEN SAID INNER AND OUTER STRIP PORTIONS, AND MEANS SUPPORTING SAID STRIP PORTIONS INCLUDING FIRST SPOKE MEANS EXTENDING RADIALLY INWARDLY FROM SAID RIM AND SUPPORTING SAID OUTER STRIP PORTION AND SECOND SPOKE MEANS EXTENDING RADIALLY OUTWARDLY FROM SAID HUB AND SUPPORTING SAID INNER STRIP PORTION, SAID INTERMEDIATE STRIP PORTION BEING SUPPORTED BY BOTH SAID FIRST AND SECOND SPOKE MEANS TO PERMIT EXPANSION OF SAID SCREEN UPON AN INCREASE IN TEMPERATURE. 